Wire-cylinder Reactor Research Articles

Effect of CO2 and Water Vapors on NOx Removal Efficiency under Conditions of DC Corona Discharge in Cylindrical Discharge Reactor

Carbon dioxide (CO2) and water vapors effects on NOx removal efficiency was studied in the wire-cylinder discharge reactor utilizing a DC power supply. The content of CO2 in both wet and dry aired initial gases was 0%, 5%, 10%, 15% and 20%, respectively. NOx treatment efficiency strongly depended on a DC positive corona discharge mode, which changed with CO2 concentration regardless the water content. A glow mode of corona discharge, established when the concentration of CO2 in the initial gas was 0% and 5%, exhibited very low removal efficiency (removal rate under 10% and energy yield about 1.1 NO g/kWh). In the cases of 10%-, 15%- and 20%-content-of-CO2 input gas, the glow corona mode was transferred into a streamer for both wet and dry initial gases. Therefore, the removal efficiency dramatically enhanced–the most efficient treatment was achieved when 15% of CO2 was included in the initial gas (5.1 NO g/kWh for wet gas and 4.8 NO g/kWh for dry gas). Water vapors played an important role in NO2 removal via the mutual reaction forming HNO3. Therefore, in the wet-air supplied reactor the highest removal rates of NOx were as high as 48%, while in dry-air supplied reactor only 15%.

A novel plasma reactor for NO/sub x/ control using photocatalyst and hydrogen peroxide injection

The authors have developed a new type of plasma reactor combining discharge plasma with a photocatalyst (TiO/sub 2/) which improves the performance of NO/sub x/ removal. This reactor is designated as a plasma-driven catalyst (PDC) reactor. The authors found that hydrogen peroxide (H/sub 2/O/sub 2/) is a very effective additive in this PDC reactor and the formation of undesirable by-product (such as O/sub 3/, N/sub 2/O) was reduced significantly. Comparative test results showed that the combination of discharge plasma with TiO/sub 2/ catalyst is a very effective method in NO/sub x/, removal over a conventional wire-cylinder reactor. NO/sub x/ was effectively oxidized to HNO/sub 3/ on the TiO/sub 2/ catalyst and trapped on the catalyst surface. Specific energy consumption of this de-NO/sub x/ process is significantly reduced, in particular, with the injection of H/sub 2/O/sub 2/.

Evaluation of pulse voltage generators

In this paper, the electrical characteristics of the positive pulsed corona in a wire-cylinder type reactor are investigated. The injected energy and charge into the discharging volume per pulse and per unit length of corona emitting wire are adopted to evaluate the power source, electric circuits, and the corona wire. The discharging current lasts from several hundred nanoseconds to a few microseconds. The current, power peak values, and the injected energy and charge per pulse per unit length of emitting wire can reach up to 60 A/m, 5 MW/m, 480 mJ/m, and 8 /spl mu/C/m, respectively. The energy conversion efficiency related to the output energy from the pulse forming capacitor and the energy delivered to the discharging volume can reach up to 90%. All results are obtained at room temperature and in air.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Oxidation characteristics of nitrogen monoxide by nanosecond pulse corona discharges in a methane combustion flue gas

The effect of nanosecond corona discharge on the NO concentrations in flue gas has been studied experimentally. Free electrons of the streamer corona originate active radicals that lead to removal of NO. The flue gas was produced by methane burning. The experiments were performed with a wire-cylinder reactor module having a nominal flue gas flow rate up to 30 Nm3h-1. Voltage pulses with amplitude up to 60 kV had a rise time 100 ns and a repetition frequency up to 800 Hz. The NO removal efficiency was 80% at an energy input to the gas of 4WhNm-3 and at oxygen concentration 4 vol.%.